|Islam, K - THE OHIO STATE UNIV.|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 3, 2004
Publication Date: November 1, 2004
Citation: Baker, B.J., Fausey, N.R., Islam, K.E. 2004. Comparison of soil physical properties under two different water table management regimes. Soil Science Society of America Journal. 68(6):1973-1981. Interpretive Summary: Environmental concerns about the water quality in streams, lakes, and coastal waters is causing changes in how water is managed on agricultural land. Farms in the Midwest typically contain some drain tiles that help move excess water from the fields to the streams allowing for timely planting of crops and to protect the crops during rainy periods. In order to reduce the amount of nutrients removed with the drainage water, drainage needs to be prevented during some periods of the year. Farmers are concerned that restricting the drainage of water from the soils will change the soil properties and make farming more difficult. This study shows there are some changes in soil physical properties when the soil is kept wetter by restricting the drainage and adding extra water by subirrigation, but the changes have not made farming more difficult. The good news for farmers and the environment is that drainage water management benefits the environment and has no adverse effect on the soil.
Technical Abstract: Soil physical properties are important indicators of the potential for agricultural production. The objective of this research was to examine the difference in soil physical properties 9-years after the initiation of two water table management (WTM) treatments in Wood County, Ohio. WTM treatments included both unrestricted subsurface drainage year round (Drainage Treatment) and subirrigation during the crop-growing season to maintain the water table at 25 cm below the surface with unrestricted subsurface drainage the remainder of the year (Subirrigation Treatment). Soil samples were collected in eight plots, in 6 depth increments to 1 meter depth. Soil aggregation and related properties were significantly different in response to WTM treatments and soil depths. The subirrigated treatment had lower aggregate stability at 40-50 cm compared to the drainage treatment. The mean weight diameter and geometric mean diameter of aggregates in the subirrigated treatment were smaller than the drainage treatment at depths of 30-75 cm. Percent macroaggregates and aggregate ratios were generally lower in the subirrigation treatment than the drainage treatment. Subirrigated soils exhibited relatively lower bulk density with an associated increase in total porosity. The drainage treatment had greater penetration resistance from 30-45 cm on readings taken in spring 2000. Subirrigated soils retain a greater volume of moisture at all energy levels except 0.00015 and 1.5 MPa. The subirrigated soils are apparently not able to develop large, stable aggregates as seen in the continuously drained soil, perhaps because of the frequent water saturation followed by slaking of soil macroaggregates associated with subirrigation.